In certain types of printing processes, an image is captured on a film through a photographic technique. Chemical solutions are applied to the film to develop and burn the image into a plate. The plate is then used in a printing press. This type of printing process is increasingly being replaced with computer-to-plate (CTP) technology.
In CTP technology, an image is captured digitally. The digital image is transmitted to a laser that acts on a film. The film typically has a dye coating laminated to a plastic film. Such films are sold commercially by Kodak and DuPont, for example. The laser burns or ablates the dye coating off to form the image. The film with the image is then exposed and imprinted onto a plate. The plate is then used in a printing press. This process is also referred to as an ablative thermal image process.
When the laser burns the dye coating on the film, certain gases and contaminants or particulates are given off. The gases may include formaldehyde, for example, or odors such as sulfur. It is desirable to clean the air in the vicinity of CTP technology.